One-at-a-time alternate dispensing method

ABSTRACT

A web roll having a pair of plies equipped with transverse perforations of a specified character which are off-set in the different plies so as to provide a source for dispensing through a force-developing nip whereby web segments issue sequentially and alternately.

United States Patent [1 1 Nystrand et al.

ONE-AT-A-TIME ALTERNATE DISPENSING METHOD Inventors: Ernst DanielNystrand; Archie S.

Krufger, both of Green Bay, Wis.

Assignee: Paper Converting Machine Company, Green Bay, Wis.

Filed: May 2, 1972 Appl. No.: 249,496

US. Cl. 225/2, 225/106 Int. Cl B26f 3/02 Field of Search 225/106, 2,100,

[ Nov. 6, 1973 [56] References Cited UNITED STATES PATENTS 400,9134/1889 Hicks .i 206/58 Primary Examiner-Frank T. Yost Attorney-Dawson,Tilton, Fallon [57] ABSTRACT 2 Claims, 6 Drawing Figures ONE-AT-A-TIMEALTERNATE DISPENSING METHOD BACKGROUND AND SUMMARY OF INVENTIONHeretofore sequential alternate dispensing of web segments has only beenachieved through interfolding. That is to say, the web segments arepartially interleaved so that as one is extracted from a positionsuitable for manual grasping, its trailing end portion insures that theleading edge portion of a succeeding interfolded segment comes into theaforementioned grasping position. Illustrative of the product and ameans and method for achieving this prior art operating is Sabee U.S.Pat. No. 2,626,145. Further illustrative of the involved expedientsemployed for providing interfolded web segments is U.S. Pat. to Greineret al. No. 3,066,932. Even though it would be most desirable to providea web segment source which would achieve this type of dispensing withoutthe elaborate machinery needed for manufacture and the involvedinterfolding, no one has been able to do so.

An ideal form of the source of web segments is a roll which can bemanufactured at high speed and with a minimum of complicated equipment.The idea of a sequential, alternate web segment dispensing roll has beenknown for many years but without avail see, for example, Hicks U.S. Pat.No. 400,913 granted Apr. 9, 1889.

According to our invention, there is provided a unique method fordeveloping a much improved roll of the Hicks type and wherein the rollis oriented for dispensing in a novel method to achieve simple,foolproof, sequential alternate dispensing of web segments.

An important feature of the invention is to provide the double web rollwith transverse perforations in each web which have slit typeperforations with two to 10 intervening bonds per lineal transverse inchand with each bond having a width of the order of 0.01 to about 0.06inches. The roll made up of the thus specified webs is developed bywinding the two webs simultaneously after the same have been perforatedincident to the unwinding of the same from parent rolls. In thedispensing of the web segments, the leading edge portion of the webplies is passed through a pressure applying nip which causes the webs toadhere together intermediate the lines of perforation but restricts suchconjoint movement when a line of perforation of one web enters theaforementioned nip.

The invention is described in conjunction with an illustrativeembodiment in the accompanying drawing, in which FIG. I is a fragmentaryperspective view of a twoweb roll incorporating teachings of thisinvention;

FIG. 2 is a side elevational view, partially schematic, of equipmentillustrating the procedure for making the roll of FIG. I;

FIG. 3 is a side elevational view, partially in section of equipmentemployed in the method of dispensing the roll of FIG. 1;

FIG. 4 is a schematic side elevational view of the equipment and roll ofFIG. 3 shown in one phase of the dispensing operation;

FIG. 5 is a view similar to FIG. 4 but showing the web roll in adifferent phase of operation; and

FIG. 6 is a schematic side elevational view corresponding essentially toFIG. 4 but which shows certain symbols applied thereto for the purposeof further explaining the technology of the invention.

In the illustration given and with reference to FIG. I the numeral 10designates generally a web roll which includes two webs 1 I and 12. Itwill be appreciated that each web may consist of one or more plies butin the simplest version will have only one ply. Each web may beconstructed of a variety of flexible material such as tissue, papertoweling, etc. Each web is relatively elongated and the two webs areconvolutely wound to form the roll 10 advantageously around a core 13which normally is constructed of paperboard.

Each web is equipped with equally spaced apart transverse lines ofperforation. For example, the web II has a first line of perforation l4and a second line of perforation IS. The web 12 has a first line ofperforation 16 and a second line of perforation I7. Thus, the line ofperforation 15 in the web 111 falls intermediate the line ofperforations 16 and 17 in the web 12. This offset arrangement continuesthroughout the length of the roll. Advantageously, the line ofperforation in one web is very close to the middle of the lines ofperforations in the other web and this spaced relationship persiststhroughout the entire length of the web roll 10.

For the purpose of developing the roll I0 of FIG. 1, the arrangement andprocedure depicted in FIG. 2 may be used to advantage. First, it will beappreciated from a consideration of FIG. 1 that by virtue of the twowebs 11 and 12 being would convolutely, simultaneously, there willnecessarily result an inner web and an outer web. In FIG. 1, the web 11is the inner web and the outer web is designated 112. In the specificarrangement seen in FIG. 2 the outer web 12 is indicated at the righthand portion of the figure and is provided by a parent roll (not shown).Normally, such a parent roll is provided on an unwind stand, thestructure and operation of which can be appreciated from a considerationof Kwitek and Nystrand, U.S. Pat. No. 2,769,600. The inner web 11 isdesignated in the upper left hand portion of FIG. 2 and is provided froma similar parent roll unwind stand arrangement.

Following the travel of the web 12 it passes (in moving toward the left)between draw rolls 18 and 19. Although these rolls are depictedschematically, it will be understood that such rolls are suitablyjournaled within side frames and serve to exert a drawing force ortension on the web 12 so as to unwind it from the parent roll.Thereafter, the web travels with and upon (for a portion of theperiphery) a perforating bedroll 20. Each of the rolls depicted in FIG.2 is suitably journaled for rotation about its own axis. Fixed to theframe (not shown) is a perforating head or knife bar 21 which coactswith the perforating bedroll 20 to develop the transverse perforations16, 17, etc. Exemplary of apparatus suitable for this perforation isthat shown in Kwitek U.S. Pat. No. 2,870,840.

As the web 12 departs from the perforating bedroll 20, it is united withthe already perforated web 11. The web 11 meanwhile has passed throughthe same sequence of operations, i.e., being drawn from its associatedparent roll by the action of draw rolls 22 and 23. A guide roll 24 maybe advantageously employed to change the direction of travel of the web111 where the parent roll providing the web 11 is physically associatedclosely with the parent roll providing the web 12. Frequently doubleroll unwind stands are employed so that the web I 1 must cross over theequipment seen in FIG. 2. The web 11 travels with and on a perforatingbedroll 25 which is equipped with its own knife bar or perforating head26. After partially traversing the periphery of the perforating bedroll25, the web 11 passes around a peel-off roll 27 which is arranged so asto detour or delay the web 11 sufficiently as to position theperforations therein (as at 14 and 15) intermediate the perforations inthe web 12 (as at 16 and 17).

The webs 11 and 12 are united for travel around a portion of theperiphery of a slitter bedroll 28. Such a roll is equipped withcircumferential grooves in which slitting wheels 29 project so that thecombined webs are now separated into a plurality of longitudinallyspaced, side by side ribbon-like segments. The width of the ribbons orstreamers depends upon the intended use. For example, with toilettissue, the roll width is 4k inches so that this then would be thespacing of the slitter wheels 29. Normally, the parent roll will have awidth which is a multiple of the width of the individual retail sizedrolls 10. Alternatively, in some instances, it may be advantageous todispense with the slitting function performed by the elements 28 and 29and perform the separation subsequently as by the use of an orbital sawsuch as can be seen in Nystrand and Bradley US. Pat. No. 3,292,470.

The joined webs 11 and 12 are thereafter caused to pass around the mainbedroll 30 which advantageously can take the form of the apparatus seenin Nystrand et al. US. Pat. No. 3,179,348. During the travel of thejoined webs 11 and 12 on the main bedroll 30, a transverse cut isperformed by virtue of a chopper roll 31 after which the webs are woundinto retail sized rolls on a mandrel-equipped turret generallydesignated 32. Details of the turret 32 can be seen in the aboveidentified U.S. Pat. No. 2,769,600.

In some instances, it may be advantageous to perform the perforation ofthe webs 11 and 12 simultaneously. In that instance, the perforatinghead or knife bar 26 may be used in conjunction with the bedroll 25.Thereafter the webs l1 and 12 are separated with the web 12 beingdesignated 12 in the central upper portion of FIG. 2 and seen passingaround a guide roll 27'. This permits the webs to be maintained in anout of phase relationship relative to the transverse perforations.

With the achievement of a web roll of the character seen in FIG. 1,dispensing is advantageously achieved through the arrangement andprocedure indicated in FIGS. 3-6.

. Exemplary of an advantageous arrangement for dispensing the websegments 33, 34, etc. (being drafted between the transverse lines ofperforation 14-15 and 16-17, respectively), is the showing of FIG. 3.There an enclosure 35 is seen to be equipped with a support portion 36for rotatably supporting roll and an output aperture 35'. In FIG. 3, thecombined webs are seen to pass between rolls 37 and 38 which define anip 39 therebetween. What occurs in this procedure can be more readilyappreciated from a consideration of FIGS. 4 and 5. In FIG. 4 the innerweb segment 33 is more than half way through the nip 39. On the otherhand, the outer web segment 34 just slightly projects beyond the nip 39.In FIG. 5, the roll 10 has been unwound somewhat more than what it wasin FIG. 4 and now the line of perforation between the segments 33 and 40in the web 11 is in the nip 39. Because of the pressure tending toconstrict the webs 11 and 12 exerted by the elements 37 and 38, furtherlongitudinal pulling or tension on the web 11 (by virtue of grasping theleading edge of the web segment 33) causes the same to be snapped off,thereby providing a discrete web segment. However, by this time, the web12 has been advanced so that now the web segment 34 is in position forgrasping. Upon the exertion of a longitudinal force, i.e., a pullingforce on the web segment 34, the webs 11 and 12 are advanced furtherthrough the nip until the line of perforation 17 in the web 12 entersthenip whereupon the segment 34 is detached. It will be appreciated thatby the time that this happens a subsequent web length in the web 11 willbe available for grasping this subsequent web segment in the web 11being the one at the trailing edge of the previously detached websegment 33. Thus, we provide an alternate sequential dispensing ofone-at-a-time web segments from a roll which is made up of two webswould convolutely with the perforations staggered or offset relative toeach other. It will be appreciated that for optimum operation the offsetshould be as close to halfway in between as is achievable commerciallybecause then the same amount of graspible web segment will project fromthe nip 39 each time.

The physical principle employed in the dispensing just described can beappreciated from a consideration of FIG. 6. FIG. 6 corresponds in thestage of dispensing essentially to that seen and described inconjunction with FIG. 5. In FIG. 6 certain symbols are applied and itwill be appreciated that the symbol T corresponds to the longitudinalpulling force exerted by a person desiring a web segment. In contrast todispensation from web rolls in the past, the force T may be close tobeing completely longitudinally extending as is possible. It is notnecessary to have any lateral component. In the past when dispensingfrom toilet tissue rolls has occurred, for example, a substantiallateral component has existed in the pulling-tearing off force.

Arranged in opposition to the force T is the force equivalent to theresistance of the roll to unwinding, here designated T The force T,, canbe further broken down into the component forces T relative to the web11 and T relative to the web 12.

Not only must the force T overcome the resistance to unwinding T,, butin addition must overcome the frictional forces f and f which resultfrom the application of the force F transverse to the longitudinallyextending forces T and T In the illustration given, the force F is thatexisting in the nip 39 defined by rolls 37 and 38. It can be developedin a number of ways and one means represented schematically in FIG. 3 isspring or biasing means 41. By spring loading the roll 38, apredetermined nip pressure can be developed on the webs l1 and 12.

The frictional forces f and f are characterized by the followingequations:

f1 IM f2 I 'Z In the above equations the symbols ;1., and arerespectively the coefficient of friction between the surfaces of thewebs 11 and 12 and the surfaces of the nipproviding elements 39 and 38.Also designated in FIG.

6 is the force f,,. This is defined by the following relationship:

f I- n The symbol n represents the coefficient of friction between theweb 11 and 12.

For the phase of the dispensing procedure illustrated in FIG. 6, it willbe appreciated that both g and F are significant. f must be large enoughto prevent relative movement between the webs 11 and 12. For quitesmooth-surfaced webs, to avoid such relative movement where thecoefficient n will be relatively low, it is necessary to correspondinglyincrease the force F, i.e., develop greater pressure on the combinedwebs in the nip 30. However, we ordinarily provide tne nipdefiningelements 38 and 39 with suitably smooth surfaces so that the frictionalforces f and f are smaller than f,,. It will be appreciated that F,,,the frictional force between the webs 11 and 12, must be greater thaneither of the frictional forces F 1 and f between the webs and theconfronting surfaces of the nip-providing elements 28 and 29.Advantageously this is achieved by providing the nip-defining elements38 and 39 as rollers which are freely journaled within the enclosure 35with one or both of the rollers 38 and 39 being spring loaded to developthe appropriate constricting force F. However, the nip-defining element38 and 39 may be stationary elements and the invention here contemplatesthe use of either or both of the elements 38 and 39 being rollers orstationary elements.

Thus, with the frictional force f being greater than either of theforces f, and f The equation representing the phase illustrated in FIG.4 is:

in equation (4) above, f does not figure because it is counterbalancedby an equal and opposite force since there is no relative movementbetween the webs. Further, inasmuch as T,, is relatively low noresistance being added to the unwinding of the roll 10, the controllingfactors are the frictional forces f and f As pointed out above, thecoefficients of friction making up the forcesf and f are also by choicequite low, the controlling factor for unreeling is the constrictingforce F. However, the force F must not be so great as to cause thecombined resistance to dispensing to exceed the strength of the webbetween perforations, viz.,

o u (I l 1 2) In the above equation, S is the dispensing strength of theunperforated web showing the necessary condition for removing webs fromthe container 35. However, the value of the constricting force F must besufficiently great as to ensure severance at a perforation downstream(after) the nip 30. This is represented by the following equation:

n u F (M: l- 2) Combining equations 5 and 6 we have:

which describes the condition necessary for the perforation on thepulled web to break and dispense one segment.

An important factor in the foregoing equation is the strength S, whichcorresponds to the strength of the perforated web at the perforation andwe find that optimum results are obtained in a cellulosic web whereinthe perforation 14-17 are of a slit of lineal type so as to provide fromabout two to about 10 bonds per inch with each bond having a width ofabout 0.01 to about 0.06 inches. By bonds, we refer to the narrowneck-like or isthmus-like portions B (see FIG. 1) which extend betweenadjacent perforations P. Where the bonds are too weak, there is the riskthat the resistance to unwinding, corresponding to the total tensionforce T required to unwind the product will be of sufficient magnitudeas to cause web separation upstream of the nip 39. Where the bondarrangement is such as to provide a cumulative strength greater thanthat which is effectively controlled by the force F, detachment of websegments at the nip 3? may not occur.

Although the method of preparing the roll 10 tends to cause the webs 11and 12 to adhere together somewhat (by virtue of their conjoint movementover the slitter bedroll 28 and the main bedroll 30), such does notinsure that the inner web 11 will always travel with the outer web 12during unreeling in the absence of the inventive dispensing procedure.For example, a sig: nificant drawback of the offset perforated rollsusedalone was that they worked only part of the time. When the inner sheet11 was grasped the outer web 12 followed. However, when the outer web 12was grasped the inner web 11 sometimes followed but sometimes wounditself around the roll 10, i.e., followed the contour of the roll 10rather than the outer web 12. By virtue of providing the nip 39 thissignal drawback is obviated.

Testing of various webs such as facial tissue and industrial embossedtoweling where the width of the webs was nine inches and the normalforce F two pounds, the force required to unwind the roll was only 0.2pounds. Since the pulling force is localized between the thumb andforefinger, the separating force at perforation is transmittedlongitudinally to just a few bonds. These few bonds break first,followed by complete separation. Thus the total strength of all thebonds may be twice or several times greater than the pulling forcerequired for separation.

On three different facial tissues with different bond patterns, thetotal bond strengths were 1.3, 1.7, and 2.5 pounds respectively, and thepulling force required was between 0.8 and 1.0 pounds. In all threecases the coefficient of friction between the plies or webs was 0.5.

On the industrial embossed toweling, the coefficient of friction betweenthe plies or webs was 0.6 and the total bond strength 12.6 pounds, witha pulling force required for separation of 2.0 pounds.

We claim:

1. A method of providing discrete, substantially identical web segmentsfor one-at-a-time sequential alternate dispensing comprising the stepsof perforating a pair of elongated webs at a plurality of equallylongitudinally spaced apart transversely extending lines, superposingsaid webs and convolute winding said webs while spacing the lines ofperforations of one web intermediate the lines of perforations of theother web to provide a web roll having a tail wherein one web projectsbeyond the other, and exerting an unwinding force on the tail of saidone web while subjecting the superposed webs to a second force generallynormal to the first mentioned force and which second force tends toadhere said webs together. 2. A method of sequential delivery of websegments alternately from a double wound web roll comprising providing aweb roll having a pair of substantially identical elongated webs eachbeing perforated at a plurality of equally longitudinally spaced aparttransversely extending lines with the lines of perforation of one webbeing intermediate the lines of perforation of the other web, exertingan unwinding force on one web while subjecting the superposed webs to asecond force gen erally normal to the first mentioned force and whichsecond force tends to adhere said webs together, advancing the first webuntil a line of perforation therein is aligned with said second force,said second force being of a magnitude sufficient to cause said pullingforce to detach a segment from said first web, and

thereafter applying a pulling force to said second web.

mg I I UNITED STATES PATENT OFFICE -CERTIFICATE OF CORRECTION Patent No.3,770, 172 Dated November 6 1973 Inventor(s) Ernst DanielNystrand andArchie S. Krueger It is certified that: error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Page 1 of the printed matter, Item [75], the name of the second inventorshould be Archie S. Krueger.

Signed sealed this 11 th day of May 1971 EAL) j q Attest:

EDWARD I/LFLE'ICHER, JR. 0'. MARSHALL 'DANN Attesting Officer vCommissioner of Patents

1. A method of providing discrete, substantially identical web segmentsfor one-at-a-time sequential alternate dispensing comprising the stepsof perforating a pair of elongated webs at a plurality of equallylongitudinally spaced apart transversely extending lines, superposingsaid webs and convolute winding said webs while spacing the lines ofperforations of one web intermediate the lines of perforations of theother web to provide a web roll having a tail wherein one web projectsbeyond the other, and exerting an unwinding force on the tail of saidone web while subjecting the superposed webs to a second force generallynormal to the first mentioned force and which second force tends toadhere said webs together.
 2. A method of sequential delivery of websegments alternately from a double wound web roll comprising providing aweb roll having a pair of substantially identical elongated webs eachbeing perforated at a plurality of equally longitudinally spaced aparttransversely extending lines with the lines of perforation of one webbeing intermediate the lines of perforation of the other web, exertingan unwinding force on one web while subjecting the superposed webs to asecond force generally normal to the first mentioned force and whichsecond force tends to adhere said webs together, advancing the first webuntil a line of perforation therein is aligned with said second force,said second force being of a magnitude sufficient to cause said pullingforce to detach a segment from said first web, and thereafter applying apulling force to said second web.